It is known that two or more vehicles moving along a roadway can cooperate as a road train or a “platoon” for mutually providing to the vehicles within the platoon various safety and efficiency benefits. A typical vehicle platoon includes a leader vehicle and one or more follower vehicles arranged serially along a single roadway lane. Larger platoons can involve many follower vehicles for providing enhanced efficiency, but ensuring the safety of to both the platooned vehicles as well as of the other non-platooning vehicles on the roadway most usually dictate the short single lane platoon incarnation.
The aerodynamic geometry of the vehicles within a platoon is a significant factor used in determining an ordering of the vehicles. As a general rule, a physically smaller vehicle following a physically larger vehicle will provide a greater benefit. Since commercial box trucks and tractors towing box trailers are in general taller and wider than most flatbed tractor trailer combinations, a maximum aerodynamic benefit and resultant fuel savings is realized by ordering vehicles classified this way such that the commercial box truck and tractors towing box trailers take the leader position(s) in the platoon, while the flatbed tractor trailer rigs take the follower position(s) in the platoon.
In addition to the above, maintaining a small distance or spacing between platooned vehicles gives greater benefit in terms of reduced energy consumption. However, holding a tight distance or spacing between platooned vehicles requires that careful attention be paid to various functional or environmental and operational characteristics and capabilities of the vehicles and other external conditions including the overall size of the platoon, weather conditions, relative braking abilities between vehicle pairs, relative acceleration abilities, relative load or cargo size and weight including required stopping distance, and the like. Special attention must also be paid to characteristics of the roadway such as roadway incline, decline, and turn radii. These various parameters implicate directly or indirectly the inter-vehicle safety considerations as well as the overall safety of multiple vehicle platoons.
In the single lane platoon incarnation described above, the vehicles participating in a platoon typically mutually cooperate to maintain a relatively fixed and constant (even or the same) distance between adjacent vehicles by exchanging deceleration command and other signals between adjacent vehicles of the platoon. On flat roadways, the even distance maintained between the vehicles is often fixed and constant in accordance with control protocols using combinations of global positioning systems (GPS) data sharing, deceleration command signal exchanges, and safety and efficiency algorithms. On graded roadways, the relatively even distance maintained between the vehicles is often modified to improve or otherwise maintain or enhance the overall safety and efficiency of the platoon. For example, the even distance maintained between the vehicles can be decreased during conditions of the platoon traversing an incline wherein the tendency of the overall platoon is to decrease speed slightly. Conversely, the even distance maintained between the vehicle can be increased during conditions of the platoon traversing a decline wherein the tendency of the overall platoon is to increase speed slightly. In any case, the relative distance between the vehicles of the platoon preferably remains substantially even, constant or the same in accordance with platoon control mechanisms and protocols in place.
For maintaining the preferred relatively fixed and constant (even or the same) distance between adjacent vehicles, many commercial vehicles that participate in platoons are highly sophisticated and are also equipped with adaptive cruise control (ACC) systems including forward and rearward sensors used for maintaining a safe relative distance between a host vehicle and a forward vehicle, and collision mitigation (CM) systems for avoiding or lessening the severity of impacts between a host and forward and rearward vehicles using various combinations of transmission, vehicle retarder, and foundation brake controls.
In addition to the above, vehicles participating in a platoon typically share their positions with other vehicles of the platoon by communicating their GPS coordinate data with other vehicles using vehicle-to-vehicle (V2V) communications (“V2V Unicast” communications), and/or vehicle-2-vehicles (V2x) communications (“V2V Multicast” communications), and/or any other suitable communications that might be available. One SAE standard is J2945 directed in general to Dedicated Short Range Communication (DSRC), and a work in process portion of that standard is J2945/6 is directed to performance requirements for cooperative adaptive cruise control and platooning. J2945/6 is intended to define the data exchange that will be necessary for coordinated platoon maneuvers, and that definition of the categories should start with differentiating between platooning and ACC, then determining message sets and performance to realize cooperative vehicles.
Currently, the technique for vehicles participating in a platoon to share their position with other vehicles of the platoon involves determining, by each vehicle, its own GPS coordinate data, broadcasting by each vehicle its own GPS coordinate data to all of the other vehicles of the platoon using over-the-air communications (such as the J2945/6 communications), and receiving the GPS position data from all of the other vehicles of the platoon. In this way, each vehicle of the platoon knows the position(s) of each other vehicle of the platoon. The GPS coordinate data is then used by each vehicle to, among other things, establish the relatively even distance coordinated between the vehicles as generally described above.
Platooning vehicles follow each other on the roadway in close proximity to each other and often at highway speeds as explained above, and for this they typically use a Radar to control the inter-vehicle distance(s). For the lateral control using automatic steering control, Lane Departure Systems track the lane markings and actively steer the vehicles between the detected lane lines and/or marks. For emergency braking situations such as Autonomous Emergency Braking (AEB) events for example, forward-directed cameras on a following vehicle detect the actuation by a forward vehicle of a rearward facing brake light so that appropriate emergency stopping or other actions can suitably be initiated.
Vehicles that operate on public roadways, however, sometimes encounter conditions that adversely affect the platoon including for example equipment failure and weather conditions. Brake lights may burn out or otherwise fails and bad weather can affect the ability of the vehicles to communicate with each other and may also affect the ability of the vehicles to communicate with remote systems such as cell towers or satellite systems. Bad weather may also impede the ability of lane marker cameras or other lane marker sensors to detect the lane lines.
Given the above, therefore, it would be helpful to provide a platooning initialization strategy to be completed between two or more vehicles while they are spaced apart by a safe distance and before they are allowed to be controlled in the platoon and placed within the mutual close proximity of the platoon. Steps of an initialization protocol should be satisfactorily completed by the vehicles before they are permitted to enter into a platooning control mode and prior to them being moved into close mutual proximity.
It would further be helpful to provide an auxiliary or redundant lamp for placement on the trailer of platooning vehicles to visually indicate to the following vehicle when an emergency stop is being demanded by the driver of the master and/or leading vehicle or if an Autonomous Emergency Braking (AEB) event is commencing on the lead vehicle.
It would be helpful to provide the auxiliary lamp as an additional brake light or lamp that would not illuminate during non-AEB events or for autonomously demanded deceleration above a predetermined level, but would selectively illuminate, however, in accordance with one or more predetermined conditions including for example: when the lead vehicle driver demands manual braking greater than a specified deceleration level, when an AEB event has commenced on the lead vehicle, or when an autonomous braking event of the lead vehicle is greater than a specified deceleration level.
It would be helpful to provide the redundant lamp as a lamp operable in a non-visible spectrum thereby providing an additional form of communication in case primary communication is not functioning properly at the time of an event.
It would also be helpful to provide an alternative mechanism for following vehicles to use as lane departure control parameters in the event of loss of an ability to sense or otherwise determine lane lines.